EC Number   |
General Information |
Reference |
|---|
   3.6.5.3 | evolution |
BPI-inducible protein A (BipA) is a member of the family of ribosomedependent translational GTPase (trGTPase) factors along with elongation factors G and 4 (EF-G and EF4). Comparison of domain arrangement and overall structure of EF-G, EF4, and BipA, overview |
758219 |
| 3.6.5.3 | evolution |
different relationships between IF5B and IF1A exist in archaea and eukaryotes, overview |
-, 758304 |
| 3.6.5.3 | evolution |
elongation factor G (EF-G) belongs to the subfamily of translational G-proteins in the GTPase superfamily. All G-proteins share a nucleotide binding G domain, which contains distinct and highly conserved elements (G1-G5). The G3 sequence motif, switch II, is highly flexible and contains a DXXG sequence |
758357 |
| 3.6.5.3 | evolution |
LepA is a paralogue of elongation factor G found in all bacteria |
-, 734798 |
| 3.6.5.3 | evolution |
the translational GTPase LepA is a highly conserved bacterial protein |
758231 |
| 3.6.5.3 | evolution |
there are three major GTPase superfamilies: small Ras-like GTPase, heterotrimeric G protein alphasubunit (Galpha) and protein-synthesizing GTPase. Underlying this functional difference are the low sequence identity (below 20%) and overall different molecular shapes among these three types of GTPases. In particular, whereas small G protein consists of a single canonical Ras-like catalytic domain (RasD), Galpha has an extra alpha-helical domain (HD) inserted and elongation factor EF-Tu has two extra beta-barrel domains (D2 and D3) subsequent to the C-terminus. In addition, Galpha can form a complex with Gbetagamma and undergoes a cycle of altered oligomeric states during function. In contrast to the functional and structural diversity, GTPases display significant conservation in the core structure of the catalytic domain. Small GTPase, Galpha, and EF-Tu contain a RasD consisting of six beta strands (beta1-beta6) and five alpha helices (alpha1-alpha5) flanking on both sides of the beta sheet. Three highly conserved loops named P-loop (PL), switch I (SI), and switch II (SII) constitute the primary sites coordinating the nucleotide phosphates. This structural similarity suggests that at a fundamental level small GTPase, Galpha, and EF-Tu may utilize the same mode of structural dynamics for their allosteric regulation, which is likely inherited from their common evolutionary ancestor. Structural comparison of Ras, Galphat and EF-Tu reveals common canonical Ras-like domain, nucleotide-associated conformational dynamics, molecular dynamics simulations, overview. Identification of EF-Tu specific key residues. But the enzymes show distinct nucleotide-associated flexibility and cross-correlation near functional regions, molecular dynamics simulations |
758105 |
| 3.6.5.3 | evolution |
unlike all other translational GTPases, the enzyme does not have an effecter domain that stably contacts the switch II region of the GTPase domain. The domain organization of enzyme IF2 is inconsistent with the articulated lever mechanism of communication between the GTPase and initiator tRNA binding domains that is proposed for the eukaryotic initiation factor 5B, eIF5B. The catalytic mechanism of enzyme IF2 appears to be unique among the translational GTPases of prokaryotes. Because the interaction of enzyme IF2 and initiator tRNA is strongest in the presence of the 30S ribosomal subunit, it is not GDP or GTP but the 30S ribosomal subunit that facilitates IF2 to interact with the initiator tRNA |
-, 735171 |
| 3.6.5.3 | malfunction |
an EF-G mutant lacking domains 4 and 5 shows ribosome-stimulated GTP hydrolysis activity 2.5fold slower than that of wild-type full-length EF-G and is insensitive to the effects of thiostrepton on both GTPase activity and ribosome binding |
-, 720597 |
| 3.6.5.3 | malfunction |
EF-G is inactivated upon formation of an intramolecular disulfide bond by Cys114 and Cys266. The enzyme is reactivated by thioredoxin, and replacement of Cys114 by serine allows H2O2-treated EF-G to support translation at the same rate as DTT-treated EF-G. Oxidation of EF-G inhibits the function of EF-G on the ribosome. The GTPase activity and the dissociation of EF-G from the ribosome are suppressed when EF-G is oxidized. With hydrogen peroxide, neither the insertion of EF-G into the ribosome nor single-cycle translocation activity in vitro is affected, while the GTPase activity and the dissociation of EF-G from the ribosome are suppressed when EF-G is oxidized. The synthesis of longer peptides is suppressed to a greater extent than that of a shorter peptide when EF-G is oxidized. The formation of the disulphide bond in EF-G might interfere with the hydrolysis of GTP that is coupled with dissociation of EF-G from the ribosome and might thereby retard the turnover of EF-G within the translational machinery |
757112 |
| 3.6.5.3 | malfunction |
EF-G mutant H91A hydrolyzes GTP at a substantially slower rate compared to wild-type EF-G |
758346 |
